1. Field of the Invention
The present invention relates to a bookbinding apparatus and a bookbinding method.
2. Description of the Related Art
Bookbinding apparatuses for biding a book using a sheet bundle composed of a plurality of pages of sheets (paper) have been known.
In a bookbinding apparatus, sheet bundles, each composed of a plurality of pages of sheets, are once accumulated in an accumulating space so as to produce a bound book by pasting and stapling the sheet bundle.
Various bookbinding methods have been proposed. As an example, a casing-in bookbinding method is known, in which the center of a cover sheet with a size larger than that of the sheet bundle (A4 sheet bundle versus A3 cover sheet, for example (Japanese Industrial Standard)) is glued at an end of the sheet bundle so as to wrap the cover sheet around the sheet bundle (see Japanese Patent Laid-Open No. 2004-155152, for example).
In the bookbinding apparatus, during printing, an interrupting factor for interrupting the printing may occur. In this case, after the printing has been interrupted and the interrupting factor has been resolved, the printing process may be restarted. When the interrupting factor for interrupting the printing is generated, part of sheets already printed may be accumulated in the accumulating space. Upon restarting the printing process, it may be economically desirable to use the already printed sheets for bookbinding to reduce paper waste. However, if any defect (sheet damage and contaminated paper) is present in the already printed sheets caused by the printing interruption or other reasons, a defective bound book may be produced as a result of using the defected printed sheets.